This is an application requesting funds to purchase a Q Exactive mass spectrometer and liquid chromatography system that will be used for quantitative proteomics research. The instrument will be integrated into the Robert Wood Johnson Medical School/Rutgers University Biological Mass Spectrometry Facility. Current instrumentation in the Facility is used at maximal capacity and we require additional capabilities to conduct quantitative proteomics experiments for thirteen NIH-funded investigators. Our user group will apply quantitative mass spectrometry to most efficiently address a wide range of important biomedical research areas including neurological disease, bacterial and viral infection, cancer, anaphylaxis, diabetes, digestive disease, and sleep disorders. Specific experiments include quantification of changes in levels and post-translational modifications of clock proteins throughout the circadian cycle, a systems biology approach to understand the lysosome and its role in human neurodegenerative disease, persistence of epitopes on protein food allergens under conditions that simulate gastric digestion, dynamics of post- translational modification of tumor suppressors during oncogenesis and analysis of pathogen-host interactions at different stages in their life cycle for hepatitis C virus, retroviruses, and chlamydia.. The requested instrument will therefore represent a significant asset to our research community and will accelerate the pace of basic and applied NIH-funded health-research at Rutgers University and the Robert Wood Johnson Medical School of UMDNJ.